# foldl -package

foldl, applied to a binary operator, a starting value (typically the left-identity of the operator), and a list, reduces the list using the binary operator, from left to right: > foldl f z [x1, x2, ..., xn] == (...((z `f` x1) `f` x2) `f`...) `f` xn The list must be finite.
foldl, applied to a binary operator, a starting value (typically the left-identity of the operator), and a ByteString, reduces the ByteString using the binary operator, from left to right.
O(n) foldl, applied to a binary operator, a starting value (typically the left-identity of the operator), and a Text, reduces the Text using the binary operator, from left to right. Subject to fusion.
O(n). Fold the elements in the set using the given left-associative binary operator, such that foldl f z == foldl f z . toAscList. For example, > toDescList set = foldl (flip (:)) [] set
foldl, applied to a binary operator, a starting value (typically the left-identity of the operator), and a ByteString, reduces the ByteString using the binary operator, from left to right.
foldl, applied to a binary operator, a starting value (typically the left-identity of the operator), and a ByteString, reduces the ByteString using the binary operator, from left to right. This function is subject to array fusion.
O(n). Fold the values in the map using the given left-associative binary operator, such that foldl f z == foldl f z . elems. For example, > elems = reverse . foldl (flip (:)) [] > let f len a = len + (length a) > foldl f 0 (fromList [(5,"a"), (3,"bbb")]) == 4
O(n). Fold the values in the map using the given left-associative binary operator, such that foldl f z == foldl f z . elems. For example, > elems = reverse . foldl (flip (:)) [] > let f len a = len + (length a) > foldl f 0 (fromList [(5,"a"), (3,"bbb")]) == 4
O(n). Fold the elements in the set using the given left-associative binary operator, such that foldl f z == foldl f z . toAscList. For example, > toDescList set = foldl (flip (:)) [] set
foldl1 is a variant of foldl that has no starting value argument, and thus must be applied to non-empty lists.
A strict version of foldl.
Fold over the elements of a structure, associating to the left, but strictly.
A strict version of foldl1
Monadic fold over the elements of a structure, associating to the left, i.e. from left to right.
'foldl\'' is like foldl, but strict in the accumulator.
O(n) A strict version of foldl. Subject to fusion.
O(n). A strict version of foldl. Each application of the operator is evaluated before using the result in the next application. This function is strict in the starting value.
'foldl\'' is like foldl, but strict in the accumulator.
'foldl\'' is like foldl, but strict in the accumulator. However, for ByteStrings, all left folds are strict in the accumulator.
O(n). A strict version of foldl. Each application of the operator is evaluated before using the result in the next application. This function is strict in the starting value.
O(n). A strict version of foldl. Each application of the operator is evaluated before using the result in the next application. This function is strict in the starting value.
O(n). A strict version of foldl. Each application of the operator is evaluated before using the result in the next application. This function is strict in the starting value.
foldl1 is a variant of foldl that has no starting value argument, and thus must be applied to non-empty ByteStrings.
O(n) A variant of foldl that has no starting value argument, and thus must be applied to a non-empty Text. Subject to fusion.
foldl1 is a variant of foldl that has no starting value argument, and thus must be applied to non-empty ByteStrings. This function is subject to array fusion.
foldl1 is a variant of foldl that has no starting value argument, and thus must be applied to non-empty ByteStrings. This function is subject to array fusion. An exception will be thrown in the case of an empty ByteString.
'foldl1\'' is like foldl1, but strict in the accumulator.
A strict version of foldl1
O(n) A strict version of foldl1. Subject to fusion.
'foldl1\'' is like foldl1, but strict in the accumulator.
'foldl1\'' is like foldl1, but strict in the accumulator. An exception will be thrown in the case of an empty ByteString.
Consume the chunks of a lazy ByteString with a strict, tail-recursive, accumulating left fold.
Consume the chunks of a lazy Text with a strict, tail-recursive, accumulating left fold.
foldlWithIndex is a version of foldl that also provides access to the index of each element.
O(n). Fold the keys and values in the map using the given left-associative binary operator, such that foldlWithKey f z == foldl (\z' (kx, x) -> f z' kx x) z . toAscList. For example, > keys = reverse . foldlWithKey (\ks k x -> k:ks) [] > let f result k a = result ++ "(" ++ (show k) ++ ":" ++ a ++ ")" > foldlWithKey f "Map: " (fromList [(5,"a"), (3,"b")]) == "Map: (3:b)(5:a)"
O(n). Fold the keys and values in the map using the given left-associative binary operator, such that foldlWithKey f z == foldl (\z' (kx, x) -> f z' kx x) z . toAscList. For example, > keys = reverse . foldlWithKey (\ks k x -> k:ks) [] > let f result k a = result ++ "(" ++ (show k) ++ ":" ++ a ++ ")" > foldlWithKey f "Map: " (fromList [(5,"a"), (3,"b")]) == "Map: (3:b)(5:a)"
O(n). A strict version of foldlWithKey. Each application of the operator is evaluated before using the result in the next application. This function is strict in the starting value.
O(n). A strict version of foldlWithKey. Each application of the operator is evaluated before using the result in the next application. This function is strict in the starting value.
gfoldl with accumulation
unfoldl f x is equivalent to reverse (unfoldr (fmap swap . f) x).